java empty catch block

Avoid Empty Catch Blocks
It’s a very bad habit to leave catch blocks empty, as when the exception is caught by the empty catch block, the program fails in silence, which makes debugging harder. Consider the following program which calculates sum of two numbers from command-line arguments:
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public class Sum {
    public static void main(String[] args) {
        int a = 0;
        int b = 0;
 
        try {
            a = Integer.parseInt(args[0]);
            b = Integer.parseInt(args[1]);
 
        } catch (NumberFormatException ex) {
        }
 
        int sum = a + b;
 
        System.out.println("Sum = " + sum);
    }
}
Note that the catch block is empty. If we run this program by the following command line:
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java Sum 123 456y
It will fail silently:
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Sum = 123

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when i tried above example i am getting different error as below istead of getting 123

public class Sum {
    public static void main(String[] args) {
        int a = 0;
        int b = 0;
 
        try {
            a = Integer.parseInt(args[0]);
            b = Integer.parseInt(args[1]);
 
        } catch (NumberFormatException ex) {
        }
 
        int sum = a + b;
 
        System.out.println("Sum = " + sum);
    }
}

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Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
      at Sum.main(Sum.java:7)

https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know

even below good catch block example also gives same error

public class SumFixed {
    public static void main(String[] args) {
        int a = 0;
        int b = 0;
 
        try {
            a = Integer.parseInt(args[0]);
            b = Integer.parseInt(args[1]);
 
        } catch (NumberFormatException ex) {
            System.out.println("One of the arguments are not number." +
                               "Program exits.");
            return;
        }
 
        int sum = a + b;
 
        System.out.println("Sum = " + sum);
    }
}

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Please advise